HD 23472 c
HD 23472 c is a super-Earth orbiting the K4 V star HD 23472 in the constellation Reticulum. It lies about 127 light-years from Earth and was discovered in 2019 using the transit method.
How Big Is HD 23472 c?
HD 23472 c has a radius of 1.87 times that of Earth. Its mass is 3.4 times that of Earth, giving it a density of 3.10 g/cm³ — between that of rocky and gaseous planets.
Is HD 23472 c in the Habitable Zone?
HD 23472 c orbits inside the inner edge of the habitable zone of HD 23472. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 23472: 0.387–0.947 AU (conservative: 0.490–0.898 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Temperature on HD 23472 c
The equilibrium temperature of HD 23472 c is about 467 K (194 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 7.96 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on HD 23472 c — one full orbit around HD 23472 — lasts 29.8 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.165 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.06).
How Was HD 23472 c Discovered?
HD 23472 c was discovered in 2019 using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is HD 23472 c?
HD 23472 c is 127.3 light-years (39.0 parsecs) from Earth. Light arriving here tonight left the planet around the year 1899. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,240,480 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. HD 23472 c scores 0.40, ranking #477 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 23472
HD 23472
- Spectral type
- K4 V
- Surface temperature
- 4,684 K (Sun: 5,772 K)
- Mass
- 0.67 M☉
- Radius
- 0.71 R☉
- Luminosity
- 0.2370 L☉
The HD 23472 Planetary System
HD 23472 c is one of 5 known planets in the HD 23472 system. Its siblings:
- HD 23472 b (Super Earth)
- HD 23472 d (Terrestrial)
- HD 23472 e (Terrestrial)
- HD 23472 f (Terrestrial)
HD 23472 c — Complete Data
| Radius | 1.870 Earth radii (0.167 Jupiter radii) |
|---|---|
| Mass | 3.41 Earth masses (0.011 Jupiter masses) |
| Density | 3.10 g/cm³ (Earth: 5.51) |
| Orbital period | 29.80 days |
| Orbital distance | 0.165 AU |
| Eccentricity | 0.063 |
| Equilibrium temperature | 467 K (194 °C) |
| Stellar irradiation | 7.96× Earth |
| Earth Similarity Index | 0.40 |
| Distance from Earth | 127.3 light-years (39.0 parsecs) |
| Constellation | Reticulum |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2019 |
Data: NASA Exoplanet Archive, last updated 2022-10-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 23472 c
Is HD 23472 c habitable?
No — HD 23472 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 23472 c?
HD 23472 c is about 127 light-years from Earth in the constellation Reticulum. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,240,480 years to get there.
How big is HD 23472 c compared to Earth?
HD 23472 c has 1.87 times the radius of Earth and about 3.4 times its mass.
How long is a year on HD 23472 c?
One orbit around HD 23472 takes 29.8 Earth days — short enough that 12 of its years would fit into one Earth year.
Explore HD 23472 c in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
